TypeError: null/undefined has no properties
當您嘗試訪問 null 和 undefined 的屬性時，會發生 JavaScript 異常 "null（或 undefined）沒有屬性"。它們沒有任何屬性。
訊息
TypeError: Cannot read properties of undefined (reading 'x') (V8-based) TypeError: Cannot destructure 'x' as it is undefined. (V8-based) TypeError: Cannot destructure property 'x' of 'y' as it is undefined. (V8-based) TypeError: null has no properties (Firefox) TypeError: undefined has no properties (Firefox) TypeError: undefined is not an object (evaluating 'undefined.x') (Safari) TypeError: Right side of assignment cannot be destructured (Safari)
錯誤型別
哪裡出錯了？
無論是 null 還是 undefined 都沒有您可以訪問的屬性。因此，您不能在它們上使用屬性訪問器，也不能對它們進行解構。
示例
null 和 undefined 沒有屬性
js
null.foo;
// TypeError: null has no properties
undefined.bar;
// TypeError: undefined has no properties